Patent Literature 1 discloses a bulb-type LED lamp including an LED (Light Emitting Diode), a case that holds the LED, and a reflection member that covers the LED. The reflection member of Patent Literature 1 has a function of expanding light distribution of the bulb-type LED lamp by reflecting partial light from the LED toward a rear side of the case (cap side). Patent Literature 2 discloses a lighting device including a reflector having a light reflection function and a plurality of light source devices arranged so as to surround the reflector. The reflector of Patent Literature 2 also has a function of expanding light distribution by reflecting emission light toward a cap side.
There is also Patent Literature 3 below as a literature related to the present technology.